A clinical trial of an automated prescreening system for cervical cancer based on image analysis of monolayers of Papanicolaou stained cells will be conducted. The diagnostic decisions are made by a two stage decision process: a cell detection module identifies objects as potentially abnormal cells; a high resolution module extracts detailed information and determines whether the object is an artifact or a cervical cell. If it is, a cell is classified as normal or abnormal. In this field trial the results obtained under the TICAS project for computer analysis of cell images, and under a NCI contract to study the information requirements for a cervical cancer prescreening device are applied. A major goal of this clinical field trial is to determine the difficulties posed by artifacts and patient to patient variability in routine clinical material. The reduction in the number of smears that would have to be visually examined by cytologists if a prescreening device based on these principles were built will be determined. This application is an extension of an existing Contract PHS NO1 CB33873 into a Grant.